Travel-control device for elevators



Dec. 3, 1929 E. B. THURSTON ET AL. 1 53 TRAVEL CONTROL DEVICE FOR ELEVATORS Filed April 50, 1927 ltl Patented Dec. 3, 1929 unrren STATES PATENT oFFice ERNEST B. THURSTON AND FRANK L. OHLER, OF TOLEDO, OHIO, ASSIGNORS TO THE HAUGHTON ELEVATOR 81; MACHINE COMJPANY, OF TOLEDO, OHIO, A CORPORATION O OHIO TRAVEL-CONTROL DEVICE FOR ELEVATORS Application filed. April 3Q,

This invention relates to the travel control of an elevator which is adapted to be driven through the frictional engagement of a rotating drum with the cables supporting the elevator, and includes means for lessening the traction on the cables, in case the drum should continue to rotate after the elevator has reached its normal limit of travel or has been stopped before reaching the same.

In the preferred installation of an elevator of this type, in order to insure the proper operation of the elevator under different loads, the cables run in grooves on the trac-' tion drum, and the frictional engagement between the cables and the grooves is suflicient to hold the traction when the difference between the loads at opposite sides of the drum is not greater than a predetermined ratio. In tall buildings, therefore, it follows that as the elevator reaches a safety stop limit, when traveling in either direction, the weight of the long reach of cables, as opposed to the counter-weights on the one hand or the weight of the car on the other hand, is suiticient to cause a continued travel of the cables if the drum continues to turn, which may sometimes lead to disastrous results.

With the above conditions in mind, it is the object of the present invention to provide improved means for stopping the travel of the cables upon the stopping of the car or the counterweights by any means provided for the purpose, even though the drum continues to rotate.

The specific construction of the invention and the advantages thereof will be more particularly explained in connection with the accompanying drawing illustrating one embodiment thereof.

lln the drawings: V

Figure 1 is a side elevation, with parts broken away, showing an elevator installation with the invention embodied therein.

Fig. 2 is aside elevation on an enlarged scale, ot the device for gripping the cables.

Fig. 3 is a plan view of the gripping device, the cables being shown in section.

Fig. 4 is a section taken substantially on' the line l4 of Fig. 3.

The installation in connection with which 1927. Serial No. 187,749.

our invention is shown, comprises an elevator car 1 adapted to travel in a hatch 2, and supported by cables 3 which pass over a rotatable drum l and are connected with counterweights 5. At the bottom of the hatch suitable butters 6 and 7 are provided for the elevator car and counterweights respectively. The usual compensating sheaveis shown at 8 supported side of the cables the bracket 12 defines a rectangular space 18 which receives a block 19 guided for horizontal movement toward the block 15. The movement of the block 19 is controlled through the medium of a rod 20 having a slotted connection 21 with the block and supporting a coil spring 22 which is adapted to exert pressure against the block, the pressure tobe exerted by the spring being adjusted by means of nuts 28 in threaded engagement with the rod. The.

inner faces of the blocks 15 and 19 are termed with grooves 2 1 to insure proper engagement with the cables.

The rods for controlling the operation of the gripping blocks for the respective reaches.

of the cables are actuated by means of hellcrank levers 25 and 26 respectively mounted on a bracket 27 which is carried by the base 13. The end of the lever 25 is connected to a small cable 28 which passes about a grooved wheel or sheave 29 at the upper end of the hatch and thence downwardly to the bottom of the hatch and about sheaves 30 and 31, the end of the cable being secured to the weight 10. The lever 26 is similarly connected to a small cable 32 which passes about sheaves 33, 34 and 35 and is also connected to the weight 10; This connection preferably includes 39 is fulcrumed at 40 near the bottom of the hatch and is provided at its inner'end with a roller 41, the intermediate portion of lever 39 being connected to the cable 28. For actuating the gripping blocks for the other reach of cables, a lever 42 is fulcrumed at 43 near the upper end of the hatch and is connected at one end to the cable 32, its other end being provided with a roller 44. Another trip lever 45 is fulcrumed at 46'near the bottom of the hatch and is provided at its inner end with a roller 47, the intermediate portion of lever 45 being connected to the cable 32.

The elevator car 1 is provided on one side with a cam 48 which under certain conditions is adapted to engage the roller.,38 to actuate the'trip lever 36, thereby actuating the lever 25 and the blocks connected therewith. The elevator car is provided with another cain 49 on the opposite side which is adapted under certain conditions to engage the roller 47, thereby actuating the trip lever 45, the lever 26 and, the blocks connected therewith. The counterweights 5 are provided on one side with a cam'50 adapted under certain conditions to engage the roller 41 on the trip lever,

39 for actuating the lever 25 and blocks associated therewith. The counterweights 5 are provided on the opposite side with a cam 51 adapted under certain conditions to engage the roller 44 on the lever 42, thereby actuating the Ilever 26 and the blocks connected therewit As an example of the conditions under which the invention may be used, it may be assumed that the elevator car 1 has a weight of 2500 pounds and is adapted to carry a maximum load of 2500 pounds. The counterweights, then, would weigh about3500 pounds, and if the elevator has a normal travel of 600 feet, the longer cable reach at the end of its movement would weigh about 2400 pounds. With such conditions, therefore, with the car traveling upwardly, if the engagement between the cables and the drum is arranged to be effective with a ratio between loads of, say, 2 to 1, it will be seen that as the car approaches the limit of its.

travel, since the weight of the long reach of cables is approximately 2400 pounds, there will be sufficient traction to cause continued travel of a lightly loaded car even when the downwardly traveling load is stopped by safety grips, bufiers or the like.

In the operation of-the present invention, as the car approaches its upper limit of travel and the counterweights 5 strike the buffers 7, the cam 50 engages the roller 41 and sets the gripping blocks to engage the cables at the upper end of the longer reach which supports the counterweights. The trip lever 36 and cam 48 on the car, however, are provided as an additional safety measure which becomes efiective in case new cables are installed and are too short. Similarly, if the car 1 approaches its lower limit of travel and strikes the buffers 6, the cam 49 will engage the roller 47 to actuate the trip for setting the blocks in engagement with the long reach of cables above the car. Under these conditions, if the cables are too short the cam 51 will engage the roller 44 and set the blocks before the counterweights 5 travel upwardly for enough to cause disaster.

' If the car is stopped by safety grips before it reaches the bottom, continued upward travel of the counterweights 5 will immediately raise the compensating sheave 8 and weight 10 and the cable 28 will at once hecome eifective for causing the block to grip the cables. Likewise, if the car should continue its upward travel after the counterweights 5 stop, the connection of the cable 32 with the counterweight 10 will set the blocks.

If the cables become stretched by continued use so that the cam 50 actuates the trip before the elevator reaches the top floor, the springs'22 may be adjusted so that their pressure does not positively stop the upward travel of the elevator, but will permit the cables to slip through the blocks until the counterweights have landed.

The lower trip arms are so located that they are actuated by the descending member at approximately the same time that the descending member strikes the buffer. This immediately reduces thetraction on the drum and at-once causes a slowing down of the ascending member at substantially the same rate as the slowing down of the descending member.

As shown in Fig. 1, it will be noted that the levers 25 and 26 are so arranged that they will be thrown past dead center position when they are actuated to set the gripping blocks but, of course, this is not essential -to the functioning of the device as a safety measure. It will also be apparent that various modifications may be made in the detailed construction and arrangement of the device without any material departure from the essential features of the invention as expressed in the claims.

l/Vhat I claim is:

1. In an elevator installation, the combination of a drum, means to rotate the drum, a cable passing over the drum, a load connected to the cable on each side of the drum, the engagement between the cable and drum being so constructed that the cable is driven in either direction that the drum rotates, means normally actuated by one load when traveling downwardly, as it approaches its lower limit of travel, to render the drum drive to reduce the efiect of the drum drive before the downwardly traveling load reaches actuating position.

2. In an elevator installation the combination of a drum, means to rotate the drum, a cable passing over the drum and having a reach depending at each side thereof, a load connected to each reach, the engagement between the drum and cable being so constructed that the cable will be frictionally driven in either direction that the drum d rotates when the weight supported at one side of the drum differs from the weight supported at the other side thereof by less than a predetermined ratio, means normally actuated by a downwardly traveling portion of the device, as it approaches its lower limit of travel, to render the drum drive inflective by disturbing said ratio, and means actuated by an upwardly traveling part of the device, in case the cable is abnormally short,

. to reduce the effect of the drum drive by disturbing said ratio before the downwardly traveling portion reaches actuating position.

3. In an elevator installation, the combination of a drum, means to rotate the drum, a cable passing over the drum and provided at each end with a load, the weight of said cable and load normally causing 'a frictional engagement between the cable and drum sufficient to drive the cable in either direction that the drum rotates, a-compensating sheave and weight below the loads and connected thereto, means actuated by a downwardly traveling part of the device, when approaching its lower limit of travel, to render the drum drive ineffective, and means connected with the compensating sheave and weight to render the drum drive ineffective in case the drum continues to turn when one of the loads is stopped at an intermediate point.

4. In an elevator installation, the combination of a drum, means to rotate the drum, a cable passin over the drum and having a reach depen ing at each side thereof, a load connected to each reach, the engagement between the cable and drum being so constructed that the cable will be frictionally driven when the weight supported at one side of the drum differs from the weight supported at the other side by less than a predetermined ratio, a compensating sheave and weight below the loads and connected thereto, means actuated by either load, as it approaches its lower limit of travel, to render the drive ineffective by disturbing said ratio, and means connected with the compensating sheave and weight to render the drum ineffective for driving in case it continues to turn when one of the loads is stopped at an intermediate point.

5. In anelevator installation, the combination of a drum, means to rotate the drum, a cable passing over the drum and having a load connected to each end thereof, the weight of said cable and load normallycausing a frictional engagement between the cable andv the drum suflicient to drive the cable in either direction that the drum rotates, a compensating sheave and weight below the loads and connected thereto, means normally actuated by a downwardly traveling part ofthe device, as it approaches its lowerlimit of travel, to render the drum drive ineffective, means actuated by an upwardly traveling portion of the device, in case the cable is abnormally short, to reduce the eifect of the drum drive before the downwardly traveling portion reaches actuating position, and means connected with the compensating sheave and weight to render the drum ineffective for driving in case it continues to turn when one of the loads is stopped at an intermediate point.

6. In an elevator installation, the combination of a drum, means to rotate the drum, a cable passing over the drum and having a load connected thereto ateach side of the drum, the connection between the cable and the drum being so constructed that the weight of the cable and load causes a frictional engagement between the cable and the drum suilicient to drive the cable in either direction that the drum rotates, a compensating sheave and weight below the load and connected thereto, and means connected with the sheave and weight to render the drum drive inellective in case the drum continues to turn when one of the loads is stopped at an intermediate point in its travel.

7. In an elevator installation, the combination of a drum, means to rotate the drum, cables passing over the drum and provided at each end with a load, gripping means located above the normal limit of elevator travel, a tripping device engageable by one of the loads as it approaches its lower limit of travel, another tripping device engageable by the other load as it' approaches its upper limit of travel, and means connecting both of said tripping devices to said gripping means to cause the latter to grip the cables, so that the first load to reach the end of its normal movement will cause the actuation of said gripping means.

8. In an elevator installation, the combination of a drum, means to rotate the drum, cables passing over the drum and provided at each end with a load, a compensating sheave and weight below the loads and connected thereto, gripping means located above the normal limit of elevator travel, a tripping device for the gripping means, and means connected with the compensating sheave and weight for actuating said tripping device in case one of the loads is stopped at an interand weight below the loads and connected thereto, gripping means located above the normal limit of elevator travel, a tripping device near the lower limit of elevator travel and engageable by one of the loads as it approaches its lower limit of travel, means connected to said tripping device for causing said gripping means to grip the downwardly traveling reach of the cables when said tripping device is so engaged, and means connected with the compensating sheave and weight for actuating said tripping device in case one of the loads is stopped at an intermediate point while the drum continues to turn.

10; In an elevator installation, the combination of a drum, means to rotate the drum,

cables passing over the drum and-provided nected thereto, gripping means located above the normal limitof elevator travel, a tripping device engageable by one of the loads as it approaches its lower limit of tra vel. another tripping device engageable by the other load as it approaches its upper limit of travel, means connecting both of said tripping devices to said gripping means to cause the lat ter to grip the downwardly traveling reach of the cables so that the first of said loads to reach the end of its normal movement will cause the actuation of said gripping means, and means connected with the compensating sheave and weight for actuating the'tripping device associated with the gripping means for the downwardly traveling reach of cables in case one of the loads is stopped at an intermediate point while the drum continues to turn.

11. In an elevator installation, the combination of a drum, means to rotate the drum,

means for the cab e, means opera le to grip said cable and comprising blocks disposed on o posite sides of the cable and means for yieldably holding said blocks against the cable with a pressure which permits the cable to slip downwardly when urged by the weight of the load, its own weight and the driving means combined, but not when relieved of said load.

13. In an elevator installation, the combination of a cable mounted for travel up or down, means operable to grip said cable and comprising a bracket defining a wedgeshaped space on one side of the cable, a vertically slidable wedge-shaped block, seating in said bracket, and a block on the opposite side of the cable guided for horizontal movement toward said wedge-shaped block, means for automatically moving said blocks into gripping relation to the cable under certain conditions, and means for yieldably holding said blocks against the cable with a predetermined pressure.

14. In an elevator installation, the combination of a drum, means to rotate the drum, a cable passing over the drum, a load connected to the cable at each side of the drum,

blocks disposed on opposite sides of the cable,

and means for yieldably holding said blocks against the cable with a pressure which permits the cable to slip, with the drum rotating, as long as both loads are carried by the cable, but not after the cable is relieved of the weight of the downwardly traveling load.

15. In an elevator installation, the combination of a cable mounted for travel up or down, a pair of gripping blocks disposed on opposite sides of said cable, a lever connected with one of said blocks and rockable to move the same toward or away from the other block, and means operable by the travel of the cable beyond a predetermined limit to rock said lever past dead center position, thereby moving the block connected there- With into cooperative relation to the other block to grip the cable.

In testimony whereof we have hereunto signed our names to this specification.

ERNEST B. THURSTON. FRANK L.. OHLER. 

